When applying tiles into your shower wall, the dimension trowel you need will depend mainly on the magnitude of the shingles. Most shower tiles for walls are modest, either mosaics or even 4-inch ceramics, meaning that a small trowel is needed for appropriate application. If you elect for bigger tiles, the trowel size will increase accordingly.
Size and Materials Matter
For mosaic tiles and glazed wall tiles up to 4 inches, then use a V-notch trowel with a notch magnitude of 3/16 inch by 1/4 inch. The notch style is what determines the total amount of mortar spread across the surface, with V-shaped utensils propagating less than U-shaped, square or even binder notched trowels. If you opt to employ bigger shower tiles in the 4-inch into 8-inch range, particularly if they’re made of natural stone, then raise the trowel notch size to 1/4-inch by 1/4-inch and put money into a U or square notch.